The present invention relates to a lighting fixture apparatus for a vehicle, and more particularly to a head lamp apparatus which is used to propagate light emitted from central light sources to head lamps through optical cables.
As described in for instance the specification of a Japanese patent application No. 7509/1992 as a head lamp apparatus for an automotive vehicle in recent years, there is an apparatus which is utilized as head lamps for the automotive vehicle by analyzing light into spectral light by a single central light source and propagating the spectral light to lighting fixtures through optical cables.
In the aforementioned head lamp apparatus, however, used is the single central light source which self-contains a single bulb. Therefore, the spectral light outgoing through the optical cables into the right and left lighting fixtures is simultaneously extinguished, in case there has occurred extinguishment caused by malfunction of the bulb itself or bulb extinguishment caused by malfunction of its control circuit. When such trouble occurs during night travelling, accordingly, it becomes instantaneously impossible to carry out a function as the head lamp apparatus.
As has been shown in an early Japanese patent publication No. 301806/1992 as another prior art, there is an example in which the optical cables are coupled to each other at their intermediate portions. However, it is difficult to produce optical cables having such a coupling structure. Moreover there occurs large optical loss at the coupling portion.
Accordingly the present applicants have filed a Japanese patent application with an application No. 161037/1993. In the Japanese patent application there is proposed a head lamp apparatus for an automotive vehicle in which all the lighting fixtures may not be simultaneously extinguished even if the bulb extinguishment is caused.
However, there is a problem that the function as the head lamp apparatus for an automotive vehicle may not be sufficiently shown because an illuminating range may not be enough obtained by only the technique proposed in the specification of the Japanese patent application No. 161037/1993.